//代码题 二、基于以下代码完成下面四个练习: 
const fp = require('lodash/fp')
const cars = [
    { name: 'Ferrari FF', horsepower: 660, dollar_value: 700000, in_stock: true },
    { name: 'Spyker C12 Zagato', horsepower: 650, dollar_value: 648000, in_stock: false },
    { name: 'Jaguar XKR-S', horsepower: 550, dollar_value: 132000, in_stock: false },
    { name: 'Audi R8', horsepower: 525, dollar_value: 114200, in_stock: false },
    { name: 'Aston Martin One-77', horsepower: 750, dollar_value: 1850000, in_stock: true },
    { name: 'Pagani Huayra', horsepower: 700, dollar_value: 1300000, in_stock: false }
]

//练习3：使用帮助函数_average重构averageDollarValue，使用函数组合的方式实现
let _average = function (xs) {
    return fp.reduce(fp.add, 0, xs) / xs.length
} //无须改动
// let averageDollarValue = function (cars) {
//     let dollar_values = fp.map(function (car) {
//         return car.dollar_value
//     }, cars)
//     return _average(dollar_values)
// }
// console.log(averageDollarValue(cars));  //790700

//*****实现代码：*****
const averageDollarValue = fp.flowRight(_average, fp.map(item => item.dollar_value))
console.log(averageDollarValue(cars)); //790700
